This invention relates to a method for hydroenhancing fabrics, and more particularly to a method for hydroenhancing fabrics using a shaped orifice wherein a liquid under pressure is forced through a non-circular orifice in a coherent jet and impinges onto a fabric. Multiple orifices are typically used, and the shape and orientation of the orifices (e.g. the distance between adjacent orifices, the angle between the major axes of the orifices and the direction of fabric travel and the direction of impingement) can be modified to effect different hydroenhancement properties. The method of hydroenhancement can be practiced using a variety of machinery configurations. One use for the method of the present invention is to impart xe2x80x9cstriping,xe2x80x9d i.e. a selective color wash-out to produce a pattern of alternating lighter and darker stripes across the width, and running the length of a fabric web.
The impingement of a liquid under pressure onto a fabric (hydroenhancement) to modify the properties of fabric materials is well known.
U.S. Pat. No. 3,560,326, Australian Patent 287,821 and Canadian Patent 739,652 to J. Bunting, U.S. Pat. Nos. 4,957,456 and 5,737,813 to Sternlieb, U.S. Pat. Nos. 5,791,028 and 6,253,429 to Zolin, and various other disclosures describe the use of pressurized liquid, usually water, exiting a manifold through an arrangement of circular orifices arranged either in a single line or in a pattern on an orifice strip; either impinging on a bat of loose fibers to make a non-woven fabric, or impinging on a fabric to change its properties.
U.S. Pat. No. 4,152,480 to Adachi, U.S. Pat. No. 4,085,486 to Brandon, and U.S. Pat. No. 3,906,130 to Tsurumi disclose the use of a single slot having a length that is equal to or greater than the width of the web of cloth being treated. In these references, the slot is arranged so as to cover the entire width of a cloth web, and the pressure of the liquid is limited due to the bending and deformation of the slot opening induced by the force of liquid pressure operating over a long unsupported length. This technology is useful for hydro-entanglement, i.e. the process of making a fabric from a loose bat of non-interwoven loose fibers, but the energy available at the maximum pressure is not adequate to appreciably alter the appearance or properties of a pre-existing fabric.
U.S. Pat. No. 4,960,630 to Greenway describes the use of a fan xe2x80x9cjetxe2x80x9d array. A fan xe2x80x9cjetxe2x80x9d has an elongated opening, usually appearing as a sector of a circle, that produces a fan-shaped spray. In the fan-shaped spray, the liquid emerges from the opening in various directions, i.e. the fan-shaped spray is not columnar or coherent.
European Patent Application 0,177,277 of Wilbanks, et al discloses a method of imparting a pattern onto fabric using jets of water that are emitted in xe2x80x9cpulses.xe2x80x9d This process is much less efficient, time wise, than the method of the present invention.
The method disclosed in U.S. Pat. No. 5,737,813 to Sternlieb could be used to create a stripe pattern, but because the energy delivered by a single circular orifice is insufficient to provide adequate wash-out, the striping effect must be produced either with a series of orifices in multiple manifolds, or by making multiple passes through one machine.
It is not feasible to simply increase the number of orifices per inch in order to deliver more energy per pass. The material that comprises an orifice strip must be of sufficient thickness to withstand the liquid pressure behind it. This thickness is usually about ten time greater than the diameter of a typical circular orifice, e.g. an orifice strip having 0.003 inch diameter (or wide) orifices can be from about 0.010 up to 0.040 inch thick. If the orifice passage was a constant 0.003 inch diameter (or width) for the full 0.040 inch of its length, the resulting stream would become divergent, i.e. would not be coherent or columnar. In order to produce coherent or columnar jet that retains its effectiveness over greater distances, an orifice passage can be relieved at the exit end. This construction reduces the effective length of the orifice passage and results in a coherent or columnar jet. A negative side effect of this construction is to create a minimum distance between adjacent orifices, in order to retain adequate material in, and strength of, the orifice strip.
It is difficult to make and maintain multiple orifice/manifolds alignment so that successive impingements fall on the same wash-out line; with the result that the striping becomes blurred. Similarly, multiple pass striping operation requires precise repeatability of fabric tracking, and also an absence of shrinkage in the width direction of the fabric throughout the time required to make the required number of passes. If the tracking deviates or width shrinkage occurs, the striping becomes blurred.
The above references describe a variety of fabric support means. Fabric support is variously described as being flat or curved, smooth or textured, non-porous or foraminous; with certain combinations of the properties being used in any given application (e.g. a curved, smooth and foraminous roll; or a flat and textured conveyor xe2x80x9cscreen;xe2x80x9d or a flat smooth and non-porous conveyor belt). Foraminous surfaces are described as being made of mesh screen material, or being a perforated sleeve. Another variable involves whether the fabric support is stationary, i.e. whether the fabric is xe2x80x9cdraggedxe2x80x9d over the support (typically referred to as an xe2x80x9cimpact boxxe2x80x9d); or is moving with, or even effecting the transport of, the fabric.
In the fabric support configurations that involve a foraminous support, the references also disclose the use of a vacuum to enhance the hydroenhancement process. The vacuum keeps the water from pooling or flooding, and thereby impeding the ability of the water jets to impinge the fabric. The vacuum can also facilitate the handling of the fabric by holding it tight to the support or support/transport member.
The above references also describe a variety of fabric transport means. Fabric transport can involve the use of a flat conveyor, or a serpentine path through a series of rolls. Additionally, the methods and apparatus of the prior art range from single-pass operations, using multiple manifolds and jet arrays; to multi-pass operations; to reciprocating operations where the fabric web travels first in one direction, then in the reverse direction, and possibly repeats this forward/reverse cycle numerous times in order to achieve a desired degree of hydroenhancement.
Further, the above references describe a variety of impingement angles, that is the angle at which a coherent jet strikes the surface of the fabric. In some cases the impingement is perpendicular to the fabric surface, but in other cases it is deliberately not.
The above references also describe methods of hydroenhancement where only one, or both sides of a fabric are subjected to the liquid jet impingement.
In the Detailed Description of the Preferred Embodiment of U.S. Pat. No. 6,253,429 to Zolin, at column 7, rows 9-12, is the statement that xe2x80x9c. . . other diameter orifices and other orifice shapes can also be employed.xe2x80x9d However, nothing in the references shows or suggests an elongated orifice shape, or an orifice other than a circle.
The present invention contemplates hydroenhancing fabrics with a liquid exiting a pressurized manifold through an array of elongated orifices. The liquid jet emanating from each elongated orifice is columnar or coherent in form, i.e. its cross section has minimum variation from where the liquid jet exits the orifice to where the liquid jet impinges the fabric. The benefits of using elongated orifices are several: to permit the presence of solid impurities in the pressurized liquid that would clog an array of circular orifices; to improve the energy efficiency of the hydroenhancement process; to reduce the number of passes required to create the desired hydroenhancement effect; to simplify the xe2x80x9cstripingxe2x80x9d of fabrics, i.e. making a consistent pattern of alternating lighter and darker lines across the width of the fabric web with a single manifold and orifice strip; to permit hydroenhancing of high-warp-count fabrics without undesirable patterning; and to simplify the machinery that would be required to accomplish any given degree of hydroenhancement.
The range of methods and apparatus that can embody the present invention are as varied as the prior art. That is, fabric support can be flat or curved, smooth or textured, non-porous or foraminous; and fabric transport can likewise be provided in many varieties.
The distinguishing characteristic of the present invention over the prior art is the use of elongated orifices. One elongated orifice that is 0.003 inch wide and 0.030 inch long can deliver approximately ten times as much energy as a circular orifice of 0.003 inch diameter. This property permits the development of hydroenhancing machines with fewer manifolds and orifice strips, resulting in less expensive equipment, and/or quicker processing times for the hydroenhancement of a fabric.
The method of hydroenhancing fabrics of the present invention comprises forcing liquid water under pressure out of a manifold through an orifice strip having a number of openings that are generally rectangular in shape. By using an orifice strip with elongated orifices, it is possible to achieve novel and reproducible striping effects at high production speeds.
The method according to the present invention can also be used to hydroenhance non-woven fabrics; provided the non-woven bats are in a cohesive condition or sate.
The present invention relates to a method for hydroenhancing fabrics using a shaped orifice that may be adapted and adjusted to optimize the hydroenhancement process, and further may be adapted to produce a variety of patterns in fabrics by varying the size, number and/or orientation of the shaped orifices. Specific features of the invention will be apparent from the above and from the following description of the illustrative embodiments when considered with the attached drawings and the appended claims.
In summary, and in accordance with the above discussion, the foregoing objectives are achieved in the following embodiments.
1. A method for hydroenhancing a fabric comprising the steps of:
(a) providing a support surface for the fabric;
(b) providing a supply of pressurized liquid;
(c) providing a manifold having a longitudinal axis and having at least one opening for the discharge of the pressurized liquid, where the opening has a length dimension that is at least one and a half times its width and the longitudinal axis of the opening is not parallel to the longitudinal axis of the manifold, where the pressurized liquid emerges from the opening as a jet;
(d) directing the liquid jet toward the support surface;
(e) interposing the fabric between the support surface and the manifold; and
(f) inducing relative motion between the fabric and the manifold.
2. The method of hydroenhancing a fabric as described in paragraph 1 where the manifold has multiple openings for the discharge of the pressurized liquid.
3. The method of hydroenhancing a fabric as described in paragraph 2 where the direction of relative motion between the fabric and the manifold is perpendicular to the longitudinal axis of the manifold.
4. The method of hydroenhancing a fabric as described in paragraph 2 where the liquid jets are directed toward the support surface in a direction that is normal to the support surface.
5. The method of hydroenhancing a fabric as described in paragraph 2 where the liquid jets are directed toward the support surface at an angle that is at least 5 degrees from normal to the support surface.
6. The method of hydroenhancing a fabric as described in paragraph 2 where the support surface is flat.
7. The method of hydroenhancing a fabric as described in paragraph 2 where the support surface is curved.
8. The method of hydroenhancing a fabric as described in paragraph 1 where the longitudinal axis of the opening is perpendicular to the longitudinal axis of the manifold.
9. The method of hydroenhancing a fabric as described in paragraph 1 where the longitudinal axis of the opening is at a non-perpendicular angle to the longitudinal axis of the manifold.
10. The method of hydroenhancing a fabric as described in paragraph 2 where the longitudinal axes of the openings are parallel and the distances between adjacent openings are equal.
11. The method of hydroenhancing a fabric as described in paragraph 2 where the longitudinal axes of the openings are parallel and the distances between adjacent openings are varied.
12. The method of hydroenhancing a fabric as described in paragraph 1 where
the opening has a liquid-entry face and a liquid-exit face and has side walls defined by elements connecting the liquid-entry and liquid-exit faces; and
the elements of the side walls are parallel so that the liquid-entry face and liquid-exit face have substantially the same size and shape.
13. The method of hydroenhancing a fabric as described in paragraph 1 where
the opening has a liquid-entry face and a liquid-exit face and has side walls defined by elements connecting the liquid-entry and liquid-exit faces; and
the elements of the side walls are divergent running from the liquid-entry face toward the liquid-exit face so that the liquid-exit face is substantially larger than the liquid-entry face.
14. The method of hydroenhancing a fabric as described in paragraph 10 where the openings have a width from about two one-thousandths of an inch to about ten one-thousandths of an inch (0.002-0.010 inch) and a length of at least twice their width.
15. The method of hydroenhancing a fabric as described in paragraph 14 where the longitudinal axes of the openings are perpendicular to the longitudinal axis of the manifold.
16. The method of hydroenhancing a fabric as described in paragraph 14 where the longitudinal axes of the openings are not perpendicular to the longitudinal axis of the manifold.
17. The method of hydroenhancing a fabric as described in paragraph 10 where:
the openings have a width from about two one-thousandths of an inch to about ten one-thousandths of an inch (0.002-0.010 inch) and a length of at twice their width; and
each of the openings has about the same width and length.
18. The method of hydroenhancing a fabric as described in paragraph 10 where:
the openings have a width from about two one-thousandths of an inch to about ten one-thousandths of an inch (0.002-0.010 inch) and a length of at least twice their width;
each of the openings is about the same width; and
the openings have varying lengths.
19. The method of hydroenhancing a fabric as described in paragraph 11 where the openings have a width from about two one-thousandths of an inch to about ten one-thousandths of an inch (0.002-0.010 inch) and a length of at least twice their width.
20. The method of hydroenhancing a fabric as described in paragraph 19 where the longitudinal axes of the openings are perpendicular to the longitudinal axis of the manifold.
21. The method of hydroenhancing a fabric as described in paragraph 19 where the longitudinal axes of the openings are not perpendicular to the longitudinal axis of the manifold.
22. The method of hydroenhancing a fabric as described in paragraph 11 where:
the openings have a width from about two one-thousandths of an inch to about ten one-thousandths of an inch (0.002-0.010 inch) and a length of at least twice their width; and
each of the openings has about the same width and length.
23. The method of hydroenhancing a fabric as described in paragraph 11 where:
the openings have a width from about two one-thousandths of an inch to about ten one-thousandths of an inch (0.002-0.010 inch) and a length of at least twice their width;
each of the openings has about the same width; and
the openings have varying lengths.
24. The method of hydroenhancing a fabric as described in paragraph 2, where the support surface is foraminous.
25. The method of hydroenhancing a fabric as described in paragraph 24, where the support surface has a first side for supporting the fabric and a second side; and
further comprising the step of providing a partial vacuum on the second side of the support surface.
26. The method of hydroenhancing a fabric as described in paragraph 2, where the fabric is moved past a stationary manifold.
27. Apparatus for hydroenhancing a fabric comprising:
a support surface for the fabric;
a supply of pressurized liquid;
a manifold having a longitudinal axis and having at least one orifice for the discharge of the pressurized liquid, where the orifice
a) has a major axis that is at least one and a half times its minor axis
b) and the major axis of the orifice is not parallel to the longitudinal axis of the manifold
c) and the pressurized liquid emerges from the orifice as a jet directed toward the support surface; and
means for inducing relative motion between the fabric and the manifold.
28. The apparatus for hydroenhancing a fabric as described in paragraph 27 where the manifold has multiple orifices for the discharge of pressurized liquid.
29. The apparatus for hydroenhancing a fabric as described in paragraph 28 where the direction of relative motion between the fabric and the manifold is perpendicular to the longitudinal axis of the manifold.
30. The apparatus for hydroenhancing a fabric as described in paragraph 28, where the fabric moves past a stationary manifold.
31. The apparatus for hydroenhancing a fabric as described in paragraph 30, where the support surface is curved.
32. The apparatus for hydroenhancing a fabric as described in paragraph 31, where the support surface is foraminous.
33. The apparatus for hydroenhancing a fabric as described in paragraph 32, where the support surface has a first side for supporting the fabric and a second side; and
further comprising means for creating a partial vacuum on the second side of the support surface.
34. The method of hydroenhancing a fabric as described in paragraph 1 where
the opening has a liquid-entry face and a liquid-exit face and has side walls defined by elements connecting the liquid-entry and liquid-exit faces; and
the elements of the side walls are divergent running from the liquid-exit face toward the liquid-entrance face so that the liquid-entrance face is substantially larger than the liquid-exit face.
35. A hydroenhanced fabric produced by following the method of:
(a) providing a support surface for the fabric;
(b) providing a supply of pressurized liquid;
(c) providing a manifold having a longitudinal axis and having at least one opening for the discharge of the pressurized liquid, where the opening has a length dimension that is at least one and a half times its width and the longitudinal axis of the opening is not parallel to the longitudinal axis of the manifold, where the pressurized liquid emerges from the opening as a jet;
(d) directing the liquid jet toward the support surface;
(e) interposing the fabric between the support surface and the manifold; and
(f) inducing relative motion between the fabric and the manifold.